How to transform an 2D sketch into an 3D object with other texture in an animation?
There would be two parts to doing that:


Scale object on one axis to turn it from 2D to 3D




If you wanted to be rotating the object in the process, you may want to parent to an empty to animate the rotation, or you could use a lattice modifier to control the deform while it is moving.


Animate from a grey texture to a realistic texture.


You can animate properties in nodes the same as any other property in blender. Use a mix node and animate the mix value to switch from one material to another.